Ok so looking at org.apache.webbeans.arquillian.standalone.OwbStandaloneContainer, where is following code, which I guess causes this problem :

    @Inject
    @DeploymentScoped
    private InstanceProducer<BeanManager> beanManagerProducer;

The same instance then occurs in org.jboss.arquillian.testenricher.cdi.CDIInjectionEnricher.